Battle of the Bismarck Sea ended large-scale Japanese attempts to reinforce New Guinea

A Japanese vessel under attack in the Battle of the Bismarck Sea on March 3, 1943.Source:Supplied

THE Japanese had been repelled at Milne Bay, pushed back at Kokoda and the Allies were undertaking the hard business of clearing them out of Papua New Guinea. All looked lost for the them and evacuation might have been a sensible policy, but the Emperor’s military commanders were desperate to keep a foothold in New Guinea.

In February 1943 they began preparations for another bold attempt to reinforce their remaining Japanese troops in New Guinea. They would send 6900 troops via a convoy across the Bismarck Sea from their stronghold of Rabaul on New Britain to Lae in New Guinea.

It was a risky venture, one that was ultimately thwarted by the RAAF and the US Fifth Air Force in what became known as the battle of the Bismarck Sea, which began 75 years ago today. It was the final failure in their desperate attempts to reinforce their men in New Guinea, but it was an Allied triumph that combined good intelligence with superior air power.

Ailled aircraft launch a low-level attack on a Japanese ship during the Battle of the Bismarck Sea in March 1943.Source:Supplied

The Japanese had captured Rabaul in January 1942, building it into a formidable base from which they launched attacks on New Guinea. Their ultimate end game was either to use New Guinea as a base to attack Australia and prevent them aiding the US war effort in the Pacific, or potentially to invade Australia.

Lae and other parts of the New Guinea mainland had been captured in March 1942. Next, was to capture the capital of Port Moresby. The first attempt was by sea, which was thwarted in the Battle of the Coral Sea in May, and then the Kokoda Track (or Trail) over the Owen Stanley Range. When the Kokoda campaign stalled thanks to stiff Australian resistance, the Japanese attempted to reinforce troops with an amphibious landing at Milne Bay, resulting in the first major defeat of a Japanese landing by a combined force of Australian and American troops.

Failure at Milne Bay led to defeat at Kokoda, followed by Allied offensives to clear the Japanese from beachheads at Gona and Buna from November 1942 to January 1943. The Japanese were left with a precarious hold and desperate need for reinforcements if they were to stay in New Guinea.

Members of the Women's Royal Australian Naval Service (WRANS) working in the General Index at FRUMEL in Melbourne.Source:News Limited

US General George Kenney.Source:News Limited

They began to plan another amphibious assault, to land around 6900 troops in New Guinea. But Allied reconnaissance aircraft quickly detected the build-up of transports in Rabaul. Their target remained a mystery, until coded radio signals were intercepted and broken by Fleet Radio Unit Melbourne (known as FRUMEL) as well as in Washington. Lae was the convoy’s destination.

Allied commanders were determined to intercept the convoy, but the Coral Sea had depleted naval forces. So the call went out to Allied air commanders in February to be ready for aerial assaults on a convoy.

In the last week of February the RAAF Beaufighter Squadron, stationed in New Guinea, was ordered to practise bombing runs on a wreck in the harbour at Port Moresby. The Beaufighter was nicknamed the “whispering death” because it was quiet but destructive.

Storms around Rabaul delayed the Japanese convoy from leaving until March 28. Reconnaissance aircraft spotted the convoy on March 1 but, when American bombers were dispatched, cloud prevented them finding the fleet. The next day, a bomber accidentally stumbled across the ships and B-17s were sent to engage. The Allies lost one B-17 but sank one troop transport before clouds again obscured the convoy.

A Beaufighter aircraft in action during the Battle of Bismarck Sea.Source:News Limited

A RAAF Bristol Beaufighter aircraft over New Guinea during Battle of the Bismarck Sea.Source:Supplied

Attacks by Allied air forces on the Japanese fleet during the Battle of the Bismarck Sea on March 3, 1943.Source:Supplied

On March 3 the Japanese ships came within range of the Allied base at Milne Bay and the RAAF Beaufighter squadron went into action. After temporarily losing sight of the fleet again, they were joined by B-17s and B-25s, who all hammered the Japanese with an awesome display of aerial firepower. Among the kinds of ordnance used were newly developed bombs that skipped along the water to bounce into the side of ships where they exploded, disabling the ships.

The Allies lost only 13 men — none of them Australian — along with four aircraft, but the battle was a disaster for the Japanese. Twenty aircraft were shot down, all eight of the Japanese troop transports were sunk along with four of the destroyer escorts. Hundreds of Japanese had to be rescued from the water. Allied pilots were under orders to not allow any troops to make it ashore. Some were even told to strafe the life rafts, but many refused.

Although about 1200 troops made it ashore to Lae, the Japanese lost 2890 men in the action. Thereafter the Japanese would not attempt another large scale attempt to reinforce New Guinea.